1. Field of the Invention
The present invention relates generally to a method of producing a turbine casing or housing and more specifically to a method of producing a turbine casing via which the capacity thereof may be reduced by simple machining.
2. Description of the Prior Art
In a previously proposed method of producing a tubine casing the scroll housing 1 thereof has been initially formed with a tongue portion 2 longer than actually required and subsequently the length thereof machined down to a desired size. However, this method has suffered from the drawback that the capacity of the turbine can only be increased by this machining process. Thus, in the case that the casting of the turbine housing is such as to produce an arrangement which has a capacity greater than that required, correction of same has been extremely difficult.
For a detailed explanation of the above mentioned arrangement reference should be made to Japanese Patent Application Pre-Publication No. Sho 54-53705.